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Schalm's Veterinary Hematology - Jain
Students should be able to perform the following tasks upon completion of this section:
3.3.1 Normal Morphology
Uniformity in size and color from cell to cell.
- 1. Dog: Cells are large (7 microns), uniform in size, and have central pallor (biconcave disc). Crenation (an artifact - pointed margins on RBC) does not readily occur.
- 2 Cat: Cells average 5.8 microns in diameter, only very slight central pallor, slight anisocytosis (variation in size of RBC), crenation is common. Up to 1% of the cells may contain Howell-Jolly bodies (nuclear remnants).
- 3. Cow: Average diameter is 6.0 microns, anisocytosis is common, ill-defined central pallor, crenation common.
- 4. Horse: Average diameter 5.7 microns, uniform in size, no central pallor.
- 5. Pig: Average diameter 6.0 microns, slight anisocytosis, no central pallor, crenation common. Polychromasia (bluish-red blood cell) and nucleated red blood cells are common in immature swine up to 3 months of age.
3.3.2 Definitions of Morphological Variations
3.3.2.1 ANISOCYTOSIS
Variation in the size of red blood cells. The large cells are most likely immature and are reticulocytes indicating early release from the marrow.
3.3.2.2 POLYCHROMASIA
Variation in the staining of red cells giving a mixture of blue and red cells. The bluish-red blood cells are generally large and represent reticulocytes. The blue color is due to residual RNA (ribosomes and mitochrondria). Associated with increased erythropoietic activity.
3.3.2.3 HYPOCHROMASIA
Decreased staining of red blood cells and increased central pallor due to a reduction of hemoglobin (Hb) in the cell. Most common cause is iron deficiency.
3.3.2.4 POIKILOCYTOSIS
Variation in the shape of red blood cells. May be pear shaped, tear shaped, etc. Should not be confused with crenation. Commonly seen in chronic blood loss, iron deficiency anemia, and occasionally in diseases characterized by increased red blood cell fragility. Poikilocytes may be removed prematurely from the circulation, potentiating the anemic state.
3.3.2.5 MACROCYTES
Larger than normal red blood cells with increased mean corpuscular volume (MCV). May exhibit polychromasia and represent reticulocytes. Can occur in B12 and folic acid deficiency anemias.
3.3.2.6 MICROCYTES
Small red blood cells with decreased MCV. Observed in iron and pyridoxine deficiency anemias.
3.3.2.7 LEPTOCYTES (Target Cells)
A thin red blood cell with increased membrane or surface area. Observed in chronic debilitating diseases and anemia.
3.3.2.8 SPHEROCYTES
Red blood cells with reduced amounts of membrane for amount of volume; opposite of leptocyte. Small, dark cell with no central pallor (observed only in the dog). Observed in autoimmune and isoimmune hemolytic anemias. May be observed following transfusions. Removed prematurely from circulation.
3.3.2.9 BASOPHILIC STIPPLING
Punctate basophilia of Wright stained red blood cells due to RNA. Occurs in the bovine and feline in responding anemias and in lead poisoning in the dog. Do not confuse with parasites.
3.3.2.10 HOWELL JOLLY BODIES
Small, round, usually eccentrically located, densely staine basophilic bodies considered to be nuclear remnants in erythrocytes. They may occur in some immature erythrocytes released to peripheral blood in response to anemia. May be increased in anemias in remissions. One percent is normal in cats. Do not confuse with parasites.
3.3.2.11 HEINZ BODIES (Schmauch bodies)
Denatured hemoglobin occurring as refractive structures formed in red blood cells as the result of the toxic effects of certain drugs or chemicals; e.g., phenothiazine toxicosis in the horse and methylene blue toxicosis in the cat. These bodies do not stain with Wright stain. Must use new methylene blue to stain the cells.
3.3.2.12 ER BODIES
Erythrocyte refractive bodies similar to Heinz bodies which may be seen in up to 10% of the red blood cells of healthy cats. Increased in a variety of diseases in the cat. May play a role in the development of anemia.
3.3.2.13 RETICULOCYTE
These cells are not found in the peripheral blood of healthy horses, cows, sheep and goats. This means that the reticulocyte matures in the bone marrow of these species before release. The absence of polychromatophilic cells in the peripheral blood parallels the long life span of these animals' red cells (140-160 days). There may be up to 1% circulating reticulocytes in healthy dogs and up to 1.5% in healthy cats. Increased reticulocytes in the peripheral blood indicate an increase in bone marrow activity and can be taken as an indicator of effective erythropoiesis in all species except the horse. The horse never has reticulocytes present in the peripheral blood. Premature release of reticulocytes under the influence of increased levels of erythropoietin, results in cells that are very large, contain more reticulum and are termed "shift" or stimulated reticulocytes. Reticulocytes normally mature in the peripheral blood between 19 and 43 hours with an average of 31 hours. They appear in the peripheral blood in about four days in response to hemorrhage or hemolysis and reach their peak by the seventh day.
3.3.2.14 NUCLEATED RED BLOOD CELL
Represents early release of immature nucleated erythroid cells, usually metarubricytes. They usually indicate a bone marrow response and are a sign of intense erythrogenesis when accompanied by polychromatophilic cells in the peripheral blood.
In cats with systemic disease, metarubricytes may be seen without a response to anemia, and may be due to the sluggish action of the spleen. Erythremic myelosis, a myeloproliferative disorder in cats, is characterized by the presence of a severe anemia and nucleated red blood cells without accompanying polychromatophilic cells or reticulocytes.
3.3.2.15 DISTEMPER INCLUSION BODY
May by observed in red blood cells. Larger than a Howell-Jolly body and takes a reddish to blue stain. Seen in a small percentage of the total cases of distemper.
3.3.2.16 . PARASITES
Located within the red blood cell or on the cell surface. Hemobartonella felis, Anaplasma marginale, Babesia canis, Babesia equi, Babesia caballi, and Eperythrozoon suis are the most common (Babesiosis = piroplasmosis).
3.3.2.17 ERYTHROCYTE SEDIMENTATION RATE (ESR)
The ESR is the rate at which the erythrocytes will fall in their own plasma in a given length of time. It is generally conducted in a Wintrobe hematocrit tube filled to the zero mark with whole blood and placed in a perfectly vertical position at room temperature. The level to which the red cells have fallen in exactly 1 hour is the ESR.
The ESR is inversely proportional to the number of red cells per unit volume of blood (PCV); i.e., the greater the PCV, the lower the ESR. It is positively influenced (increased) by the tendency toward rouleaux formation and the concentration of fibrinogen and globulin. Reticulocytes, leptocytes and nucleated red cells do not readily participate in rouleaux formation. When they are present in significant numbers, the observed ERS is usually less than the anticipated value for the PCV (negative ESR). Under these conditions, the ESR often exhibits a diphasic pattern. Hypoproteinemia is also characterized by a negative corrected ESR value. In order to evaluate the influence of disease upon the ESR, it is necessary to correct the observed ESR by subtracting from it the anticipated rate due entirely to the ratio of cells to plasma. When the PCV is equal to or greater than 50%, no settling of erythrocytes within a 60-minute period is observed except in the presence of grave disease. The observed ESR minus the anticipated ESR equals the corrected ESR (positive or negative).
There is little or no erythrocyte sedimentation in healthy ruminants since the erythrocytes show little natural tendency to form rouleaux. Therefore, when significant rouleaux formation is seen in bovine blood films, it should be interpreted as reflecting a grave disease process.
Remember: "Observed ESR - Anticipated ESR = Corrected ESR."
The bone marrow examination is seldom diagnostic; but, like other clinical and laboratory procedures, it constitutes a link in the chain of evidence which is often of value in diagnosis when correlated with other information.
The primary function of the bone marrow is the production of erythrocytes, granulocytes (neutrophils, eosinophils and basophils) and thrombocytes. Bone marrow which is active in this respect is red in color and is called red marrow; whereas, non-productive resting marrow is called yellow marrow. Yellow marrow consists of three types of cells: endothelial, reticular and fat cells.
In the adult, yellow marrow fills most of the shaft of the long bones. Demands for increased production of blood cells are met by conversion of yellow marrow into red marrow. Red marrow expansion or regression is made possible through its ability to interchange with fat cells.
Red marrow is found throughout life in flat bones (vertebrae, ribs, pelvis and bones of the head) and the proximal ends of long bones (femur, humerus).
Accurate classification of the immature cells of the granulocytic and erythrocytic series requires much study and practice. It is helpful to study color plates of cells of bone marrow and blood films.
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Needed for the production of globin in hemoglobin. Abnormal erythropoiesis may occur in a protein deficient diet.
Essential vitamins for erythropoiesis are in the B series. All may not be required by every species of animal, but deficiencies of the following may lead to development of anemia:
The primary function of the erythrocyte is to serve as a carrier of Hb and Hb functions as a carrier of oxygen.
Hemoglobin is a conjugated protein consisting of heme and globin. It has a molecular weight of approximately 64,000-68,000 and can pass an intact glomerular membrane. Each molecule consists of 4 heme units and 4 globin units
Hb may be released and degraded intravascularly or extravascularly.
- a. Free Hb in the plasma is first bound to haptoglobin, an alpha 2 mucoprotein formed in the liver, and the complex is then removed rapidly and degraded mainly by the liver.
- b. Excess Hb in the circulation is converted to methemoglobin, which in turn dissociates, liberating hematin. Hematin is bound first to hemopexin, a glycoprotein present in the plasma, and the hematin-hemopexin complex is removed from the plasma by the hepatocytes.
- c. When more free Hb is present than is required to saturate all the plasma haptoglobin, it is filtered by the renal glomeruli and absorbed in the proximal tubular epithelium where it is broken down to bilirubin.
- 1) This bilirubin is rapidly transported to the liver for excretion into the bile.
- 2) When the renal threshold for Hb is exceeded, Hb spills into the urine and the condition is referred to as hemoglobinuria.
Extravascularly, Hb is broken down by the reticuloendothelial system (RES) into hemotoidin which unites with a plasma protein and becomes hemobilirubin (indirecting-reacting, unconjugated or free bilirubin). Hemobilirubin is then transported to the liver where it is conjugated with glucuronic acid to become cholebilirubin (direct-reacting, conjugated or bound bilirubin).
- a. In dogs, the kidney threshold for the conjugated bilirubin is low permitting bilirubin pigments to appear readily in the urine in many systemic diseases.
- b. In severe hemolytic icterus, both forms of bilirubin may be found in the plasma with hemobilirubin predominating.
- c. The horse is unique in that in both normal and disease conditions, the bilirubin in the plasma is primarily indirect-reacting or hemobilirubin due to the low renal threshold for cholebilirubin.
The erythron can be evaluated by the total red blood cell count, hematocrit or packed cell volume (PCV), and the Hb concentration.
The word "hematocrit" means to separate blood. It is the percent of blood composed of erythrocytes. The PCV is obtained by centrifugation.
3.7.2.1 METHODS FOR OBTAINING HEMATOCRIT OR PCV
3.7.2.1.1 WINTROPE HEMATOCRIT METHOD
- 1) Tube is calibrated longitudinally into 10 cm
- 2) The numbers on the right of the tube read from 0 to 10 cm and are used for the PCV determination.
- 3) The numbers on the left of the scale read from 0 to 10 cm and are used for the ESR.
- 4) The tube must be filled by means of a special pipette or disposable pipette that is long enough to reach the bottom of the tube.
- 5) Centrifuge tube between 3000-4000 rpm for a minimum of 30 minutes (60 min. for cattle, sheep and goat).
- 6) Read the scale at the top of the packed erythrocytes, immediately adjacent to the buffy coat.
- 7) Multiply the number obtained by 10 for volume per deciliter since the PCV is reported as percent.
- 8) The advantages of this method are:
- a) can estimate the total WBC count from the buffy coat
- b) can determine the icterus index
3.7.2.1.2 MICROHEMATOCRIT METHOD
- 1) Capillary tubes (75 mm x 1.0 mm) are filled approximately three fourths from the end with blood by capillary action.
- 2) Seal end and place in the microhematocrit centrifuge with the open end toward the hub and the seal end toward the rim.
- 3) Place cover plate securely over tubes and centrifuge for 5 min. at 10,000-15,000 rpm.
- 4) Remove tube and read percent of PCV using the hematocrit reader.
- 5) The reader chart requires that the tube be placed on the scale with the meniscus of plasma on the top line. Slide the tube until the bottom of the erythrocyte layer corresponds with the zero line. The line that intercepts the top of the erythrocyte layer is recorded as the value of the PCV.
- 6) The advantage of this method are:
- a) It is accurate and reproducible
- b) It requires only 5 minutes
- c) It requires a minimum amount of blood
- 7) The disadvantages of this method are:
- a) A special reader is required to determine the value.
- b) The buffy coat and the icterus index are not so easily determined due to the small size of the tube.
3.7.2.2 Interrelationship of Packed Cell Volume (PCV), Hemoglobin (Hb) and RBCs
- a. When the blood is composed of normocytic erythrocytes, a relationship can be anticipated to exist between the PCV and the number of erythrocytes. A rough estimate of RBC numbers can be obtained by dividing PCV by 6 and stating the results in millions.
- b. It is possible to estimate the Hb concentration of a blood sample by dividing the PCV by a factor of 3.
- c. When the Hb is obtained by an accurate method, it is possible to predict the PCV by multiplying the Hb value by a factor of 3.
When blood is centrifuged in the Wintrobe tube or the small capillary tube it is separated into 3 compartments.
3.7.3.1 PLASMA COMPARTMENT
- a. The plasma volume normally exceeds 50% of the whole blood.
- b. The color is slight yellow due to bilirubin, a product of hemoglobin catabolism.
- c. The yellow color of the plasma increases in hemolytic anemia, acute liver necrosis and bile duct obstruction.
- d. The degree of yellow pigmentation of the plasma is referred to as the icterus index which is compared against a dilution of potassium dichromate.
- e. In Carnivorous animals, such as the dog and cat, the yellow color is due entirely to bilirubin.
- f. In these animals the icterus index is less than 5 units. Greater than 7.5 units is abnormal.
- g. In the cow and horse, the yellow pigments Carotene, Cartenoid and Xanthophyll of plants and vegetables add additional color to the plasma.
3.7.3.2 BUFFY COAT
- a. Occurs immediately below the plasma compartment and directly above the packed red cell.
- b. It consists of a white to gray layer.
- c. Thrombocytes are at the top of the buffy coat with leukocytes below.
- d. Reticulocytes, if present, would be found below the leukocytes at the top of the packed erythrocytes.
- e. The amount of buffy coat may be used to estimate the total WBC count using the Wintrope tube.
- 1) According to Wintrope, each 0.1 mm of the first 1 mm = 1,000 leukocytes. Whereas each 0.1 mm beyond the first 1.0 mm is equal to 2,000 leukocytes.
- f. However, for clinical application, a buffy coat of less than 0.5 mm would suggest leukopenia while above 1.5 mm indicates a leukocytosis.
- g. A red-tinged buffy coat is due to an admixture of leukocytes and abnormal erythrocytes, reticulocytes or nucleated red cells.
3.7.3.3 PACKED ERYTHOCYTES
- a. Column of packed erthrocytes is expressed as percentage of the total volume.
- b. Anemia exist when the PCV falls below minimum normal range.
- c. The PCV must always be interpreted in light of the water balance of the animal as determined by physical examination and estimation of the total proteins.
- 1) If the PCV exceeds the maximum, hemoconcentration may be present.
- 2) An anemic animal with hemoconcentration may be have a PCV in the normal range.
- d. The PCV has the best sensitivity and reproducibility of the total red count and the hemoglobin determination.
3.7.4.1 . OXYHEMOGLOBIN
- a. Measures oxyhemoglobin directly by its absorption using a green filter.
- b. Test is simple and quick with an accuracy of +/- 10%.
- c. The Spencer Hemoglobinometer can be used for this test.
3.7.4.2 CYANOMETHEMOGLOBIN
- a. The Hb is converted to cyanomethemoglobin by the cyanide in the diluting fluid and then read in a calorimeter.
- b. The concentration of cyanomethemoglobin is directly proportional to the optical density.
- c. This method is very excellent and precise. It measures all forms of hemoglobin most likely to be in the blood except sulfhemoglobin.
3.7.4.3 ACID HEMATIN
- a. Red blood cells are lysed in dilute HCL to form acid hematin which is brown in color.
- b. This brown color is then matched with color standards.
- c. Several instruments made on acid-hematin principle are:
- 1) Sahli-Haden
- 2) Haden-Hauser
- d. Not a good method in that the error encountered may be up to 15% due to:
- 1) Rate of conversion of Hb to acid-hematin varies with time and temperature.
- 2)Inaccuracy of visual color matching.
- 3)Color intensity not directly proportional to Hb concentration when values are abnormally high or low.
3.7.4.4 DIRECT MATCHING
- a.Hemoglobin is determined by comparing the color of blood on blotting paper with lithographed color standards.
- b.Color may also be compared against artificial standards by transmitted light through instruments such as Tallquist and Dare.
- c.A very poor method since the margin of error is about 20-50%.
An increase above normal in the total red blood cell count, hemoglobin, and the PCV.
3.8.1.1 .ABSOLUTE POLYCYTHEMIA
May be physiologic or pathologic, although change may be only slight or transitory.
a.PHYSIOLOGIC
Seen in splenic contraction where reserve blood cells are released into circulation. Most common in cats and horses due to epinephrine release associated with fear, excitement and exercise. The total protein value is not affected and should remain normal. May also be seen in animals at high altitude due to decreased atmospheric oxygen.
b.PATHOLOGIC
Hypoxia observed in heart and lung disease will stimulate the production of erythropoietin and therefore produce polycythemia. Polycythemia rubra vera is a rare disease that has been reported in dogs, cats, cattle and man. All cellular elements of the bone marrow are affected. There is an absolute increase in the numbers of erythrocytes and total blood volume; however, the total protein remains the same.
3.8.1.2 RELATIVE POLYCYTHEMIA (HEMOCONCENTRATION)
An increase in the PCV, red blood cell count and hemoglobin due to a loss of water from the blood (decrease in plasma volume). The plasma protein concentration is elevated. May be observed in clinical dehydration associated with vomiting, diarrhea, reduced water intake, diuresis and shock.
3.9.1.1 Red Blood Cell Size
The size of the red cell is determined by visual interpretation on a stained blood smear or more accurately by the mean corpuscular value.
PCV X 10 = MCV (femtoliters, fl)
RBC Count (millions)
3.9.1.1.1 MACROCYTIC (INCREASED MCV)
Transitory macrocytic condition is observed in cases where the marrow is responding to increased red blood cell need and discharging more immature cells (reticulocytes and nucleated red cells), which are larger, into the peripheral blood. e.g. Blood loss or hemolysis.
True macrocytic is observed in conditions where there is interference with maturation in the prorubicyte - rubricyte stage and reduced cell division resulting in large cells being released into the blood. e.g. B12, folic acid like deficiency seen in miniature poodles.
3.9.1.1.2 NORMOCYTIC (Normal MCV)
There is interference with erythropoiesis at the stem cell level resulting in fewer cells entering the maturation process. Those that do enter the process develop normally and are released at the normal time. e.g. selective anemias of chronic infections, chronic renal disease, chronic liver disease and aplastic anemias.
3.9.1.1.3 MICROCYTIC (Reduced MCV)
This is the type seen in iron deficiency anemia. A deficiency in iron results in less Hb being formed. Since the cell stops division when a certain critical hemoglobin concentration is reached, in iron deficiency there is often an extra division resulting in smaller cells. e.g. iron, copper and pyridoxine deficiency.
3.9.1.2 HEMOGLOBIN CONCENTRATION
Determined by prominence of central pallor in stained smear and more accurately by the mean corpuscular hemoglobin concentration (MCHC) and mean corpuscular hemoglobin (MCH)
MCHC = Hb x 100 = Grams/deciliter (d/dl)
PCV
MCH = Hb X 10 = Picograms (pg)
RBC
3.9.1.2.1 .HYPERCHROMIC
The cell can not become supersaturated with Hb so this state does not actually exist. The MCH may be increased in cases where the MCV is elevated but not the MCHC. Elevated MCHC may indicate free hemoglobin in the plasma due to hemolysis, Heinz bodies in RBCs, or to excessive amounts of EDTA which cause shrinkage of RBCs.
3.9.1.2.2 Normochromic
Normal Hb concentration is found in most anemias of animals.
3.9.1.2.3 Hypochromic
Reduced Hb concentration is characteristic of iron, copper and pyridoxine deficiency anemias, and in blood loss and hemolysis where the number of immature cells greatly exceeds the number of mature red blood cells.
3.9.2.1 REGENERATIVE
The bone marrow is capable of responding to the anemia by increasing its production of red blood cells. The ability to respond with increased activity indicates that the site of pathologic alteration is not in the bone marrow. i.e. blood loss and hemolytic anemias. Signs of increased erythrocyte production by the bone marrow may include:
- Reticulocytosis
- Polychromasia
- Basophilic stippling
- Anisocytosis
- Nucleated red cells
- Howell-jolly bodies
3.9.2.2 NON-REGENERATIVE
The bone marrow is not able to respond to the anemic state. In fact, the inability of the marrow to produce red blood cells is the reason for the anemia. Therefore regenerative signs are absent. Red Cell morphology is normal in depression anemias and aplastic anemias.
- 2)External vs Internal Acute Blood Loss
External blood loss results in a reduction of red blood cells, plasma proteins, and plasma volume. Iron is lost to the exterior and not available for utilization.
Acute blood loss seldom results in iron deficiency since adults generally have sufficient iron stores to regenerate 2-3 times the total blood volume of red blood cells.
Internal blood loss is primarily into body cavities, 2/3 of the blood is reabsorbed by the lymphatics (completed in 24-72 hours) while 1/3 is broken down by the RE system. If a large amount of blood is broken down it may simulate a hemolytic anemia (hyperbilirubinemia).
- 3)Response
The response following acute hemorrhage depends upon the amount of blood loss, period of time during which bleeding occurs and the site of hemorrhage.
- a)Initially only the blood volume is reduced. The animal may be in shock due to blood loss (hypovolemia). The plasma and cells are both lost and may present as a normal hemogram.
- b) Thrombocyte numbers increase during the next few hours.
- c)Three hours later, a neutrophilic leukocytosis derived from the marginal pool occurs.
- d)Starting at 2-3 hours and proceeding to 48-72 hours, the blood volume is restored by the addition of fluid resulting in reduced PCV, Hb, and red blood cell numbers (anemia). Plasma protein concentration is also reduced. No regenerative signs are present at this stage.
- e)At 72-96 hours, the signs of increased red blood cell production are evident in the peripheral blood. i.e. polychromasia, nucleated red blood cells (NRBC), reticulocytosis. May actually have an elevated MCV at this stage due to large young cells.
- f)Leukocytosis with left shift may accompany red cell response due to dual stimulation of bone marrow.
- g)Hemogram returns to normal in 1-2 weeks after a single acute episode. PCV returns to normal more rapidly than red blood count and Hb because of the large size of young cells.
- h)If reticulocytosis persists longer than 2-3 weeks look for continuous bleeding.
Damaged red blood cells (by intrinsic or extrinsic means) may lyse within the circulation (intravascular hemolysis) or be phagocytized by the reticuloendothelial cells (extravascular hemolysis). In many cases, hemolysis takes place in both locations but one will usually predominate.
The laboratory picture of hemolytic anemia will vary according to the clinical course and site of hemolysis
Site of the problem is in the bone marrow in contrast to peripheral blood, as is the case in hemorrhagic and hemolytic anemias.
The bone marrow can usually respond but in an ineffective manner. Red blood cell size and Hb content may vary.
Functions in nucleic acid metabolism. Results in a macrocytic anemia.
Required for B12 synthesis in the ruminant.
The remainder is in myoglobin, enzymes of the cytochrome oxidase system and stored iron.
An abnormal proliferation of a variety of bone marrow cells that leads to a profound non-regenerative anemia. It is primarily a bone marrow disease and believe to be caused by a C-type leukemia virus. See large numbers of nucleated red blood cells without reticulocytes or polychromatophilic cells.
History, physical examination, and clinical signs often suggest the presence of an anemia. i.e.: weakness, lack of stamina, pale mucous membranes, icterus, hemorrhage, melena.
The presence of anemia is confirmed by PCV, Hb and/or total red blood cell count. The PCV is most suitable for the practitioner's laboratory. Most commercial laboratories use automatic equipment which does all 3 determinations as well as figure the indices (i.e. MCV, MCHC) and allow you to make a morphologic classification. (i. e. normochromic, etc.)
Once the presence of an anemia is confirmed then it should be classified as regenerative or non-regenerative and the red blood cell morphology determined by examining a blood smear and/or doing a reticulocyte count.
Since regenerative signs are never present in the peripheral blood of the horse, a bone marrow examination is the only way to detect a regenerative response in this species. Young swine normally have anisocytosis and polychromasia. Reticulocyte counts up to 10% or higher indicate regeneration.
Examine the mucous membranes and plasma for icterus (hyperbilirubinemia) and the urine for hemoglobinuria (evidence of hemolysis). The determination of the nature of any hyper-bilirubinemia (indirect or direct Van-Den Bergh) would be helpful.
With information derived from the above tests and observations, which are easily done in any practice, one can do a good job in determining the pathogenic mechanism involved and often discover the etiology.
A..A lack of bone marrow response, normocytic normochromic red blood cells, and no evidence of icterus or hemoglobinuria would suggest:
B.Presence of a regenerative response but no icterus or hemoglobinuria suggests:
C.Presence of a regenerative response in combination with icterus or hyperbilirubinemia, bilirubinuria, and hemoglobinuria suggests:
D.Presence of a regenerative response accompanied by icterus or hyperbilirubinemia but no hemoglobinuria suggests an anemia resulting from extravascular hemolysis.
E.Anemias which may be regenerative or non-regenerative but where abnormal red blood cells are present.
An acquired hemolytic disease in which the life span of the RBC is shortened due to the coating of the cell by an abnormal globulin. The animal (primarily in the dog) forms antibodies (autoantibodies) against its own RBC's. The membrane of these RBC's is altered and the cell is removed prematurely by the RE system (extravascular hemolysis). Two main forms of AIHA are noted in the dog.
